Known flame detectors of a type used in oil refineries and chemical plants often include triple band infrared sensing structures. Such flame detectors currently available in the marketplace are usually sold in fixed configurations. Customers order flame detectors that are either tuned to detect hydrocarbon fires (petroleum products) or non-hydrocarbon fires (hydrogen).
The detectors are tuned to either of these two fire types by the selection of particular wavelength filters that are placed in front of an infrared radiation sensor, such as, for example, a pyroelectric sensor. In known detectors, the filters are permanently affixed to the detectors. Infrared filters usually pass wavelengths of 2-6 microns. Known flame detectors often use three or four channels.
It would be advantageous to be able to easily change the sensing characteristics or, personality of the detector by quickly changing the set of filters in the product. The filters could be factory installable, or field installable.